3 ms·

Actually I'm very surprised (read skeptical) of the precision and firmness of the claims in this article. For example "...the nautical mile – 1.852 kilometers

Actually I'm very surprised (read skeptical) of the precision and firmness of the claims in this article. For example "...the nautical mile – 1.852 kilometers – was introduced in the 15th century..." For one thing, there was effectively no international standardization on other units in the 15th century. Indeed different countries did not even agree on the current calendar date. So the claim that the knot was precisely international defined in the 15th seems incredible. Also, the diameter of the earth was quite controversial in the 15th century (Columbus notoriously used a very low-ball figure to raise funds for his westward expedition to China). So it seems unlikely a precise figure for the length of a minute of arch could be agreed on and less likely that it would be accurate.

bunderbunder 13y ago
It certainly wouldn't have been precisely internationally defined in terms of a unit of measure that didn't exist until about four centuries later.
mjlee 13y ago
I think the author has become a little confused by what nautical mile means today and has meant in the past. Originally (maybe as far back as the 15th Century) a nautical mile was just 1 minute of arc of the Earth's circumference no matter where you were on the Earth. A nautical mile at the pole would be quite short, a nautical mile at the equator would be quite long.
- ErsatzVerkehr 13y ago
  > A nautical mile at the pole would be quite short, a nautical mile at the equator would be quite long. No, this is emphatically not the case. You're confusing a minute of curvature -- a minute along a great circle path -- with a minute of latitude.
  - mjlee 13y ago
    A minute of latitude was the originally definition of the nautical mile. I'm not exactly sure when it changed to be defined as the mean nautical mile. I'm not talking about how it is today, I'm talking about the inconsistencies in this article.

bunderbunder 13y ago

It certainly wouldn't have been precisely internationally defined in terms of a unit of measure that didn't exist until about four centuries later.

mjlee 13y ago

I think the author has become a little confused by what nautical mile means today and has meant in the past. Originally (maybe as far back as the 15th Century) a nautical mile was just 1 minute of arc of the Earth's circumference no matter where you were on the Earth. A nautical mile at the pole would be quite short, a nautical mile at the equator would be quite long.

ErsatzVerkehr 13y ago
> A nautical mile at the pole would be quite short, a nautical mile at the equator would be quite long. No, this is emphatically not the case. You're confusing a minute of curvature -- a minute along a great circle path -- with a minute of latitude.
- mjlee 13y ago
  A minute of latitude was the originally definition of the nautical mile. I'm not exactly sure when it changed to be defined as the mean nautical mile. I'm not talking about how it is today, I'm talking about the inconsistencies in this article.